1. Field of the Invention
The present invention relates to a method for producing mycophenolic acid by fermentation.
2. Description of the Prior Art
Mycophenolic acid (hereinafter referred to as MPA) is a compound with several useful biological properties such as antiviral and antitumor activities (K. Ando et al., J. Antibiot, 21, 649-652, 1968 and R. H. Williams et al., J. Antibiot, 21, 463-464, 1968).
It has also been reported that MPA has antimicrobial activity (K. Gilliver, Ann. Bot. (London) 10, 271-282, 1946). MPA was initially isolated from a culture of a fungus belonging to the genus Penicillium and it is known that MPA is produced by many species of the genus Penicillium. For example, P. brevi-compactum, P. stroniferum, P. scabrum, P. nagemi, P. Szaferi and P. patus-mai, (Biochem. J. 27, 654, 1933). Recently, it has shown that a mutant of the genus Penicillium resistant to polyen- antibiotics produces more MPA than a parent strain (Japanese Published Unexamined Patent Application No. 115880/1978). A need, however, continues to exist for an improved technique of producing MPA in large quantities by a commercially acceptable technique.